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61.
Annona crassiflora, known commonly as araticum, is an exotic tropical fruit consumed mainly by native people of the Brazilian Cerrado (2nd biggest biome of Brazil). In this study, pulp, seed, and peel of slight ripe and overripe fruits were extracted using ethanol and water. The extracts showed high content of total phenols and were screening for their potential as antioxidants using the in vitro model 1,1‐ dipheniyl‐2‐picryl hydrazyl (DPPH). The ethanol extracts of peel and seeds showed IC50 of 48.82 μg/mL and 31.14 μg/mL, respectively, for the slightly ripe fruits. As the ethanolic fractions of araticum showed the highest antioxidant activity, they were selected for testing of its effect on lipid peroxidation. The ethanolic extracts of slightly ripe fruits showed IC50 of 4.44 μg/mL, 1.72 μg/mL, and 8.62 μg/mL for the peel, seed, and pulp, respectively. This is the 1st report on the antioxidant properties of the extracts of araticum. Owing to these properties, the studies can be further extending to exploit them for their possible application as natural antioxidant for cosmetic, supplements, and functional ingredients for food products.  相似文献   
62.
This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al2O3 catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl form). The catalysts were leached with aqua regia (75 °C, 20-25 min). Platinum adsorption was influenced by the presence of other metals which form chlorocomplexes (tin, indium) and also base metals (aluminum). However, it was possible to overcome this fact by a sequential desorption procedure. Aluminum was selectively removed from the resins by elution with 3 mol L−1 HCl. Platinum was desorbed passing 1 mol L−1 Na2S2O3 (pH 9). Tin was removed by elution with 0.1 mol L−1 ascorbic acid. Indium was removed using 0.1 mol L−1 EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%).  相似文献   
63.
Pd-loaded Ce0.6Zr0.4O2 solid solutions supported on Al2O3 are investigated as catalysts for the reduction of NO by CO. The attention is focused on the role of the Ce0.6Zr0.4O2 and of the Pd dispersion on the catalytic activity. The system shows a very high activity below 500 K, which is almost independent on the Pd dispersion. The high activity is attributed to a promoting effect of the Ce0.6Zr0.4O2 on the NO conversion. Investigation of the influence of high temperature treatments disclosed a thermal stabilisation of both Ce0.6Zr0.4O2 and Al2O3 in the Ce0.6Zr0.4O2/Al2O3 system.  相似文献   
64.
Polyphenols, occurring in fruit and vegetables, wine, tea, extra virgin olive oil, chocolate and other cocoa products, have been demonstrated to have clear antioxidant properties in vitro, and many of their biological actions have been attributed to their intrinsic reducing capabilities. However, it has become clear that, in complex biological systems, polyphenols exhibit several additional properties which are yet poorly understood. Apoptosis is a genetically controlled and evolutionarily conserved form of cell death of critical importance for the normal embryonic development and for the maintenance of tissue homeostasis in the adult organism. The malfunction of the death machinery may play a primary role in various pathological processes, since too little or too much apoptosis can lead to proliferative or degenerative diseases, respectively. Cancer cells are characterized by a deregulated proliferation, and/or an inability to undergo programmed cell death. A large body of evidence indicates that polyphenols can exert chemopreventive effects towards different organ specific cancers, affecting the overall process of carcinogenesis by several mechanisms: inhibition of DNA synthesis, modulation of ROS production, regulation of cell cycle arrest, modulation of survival/proliferation pathways. In addition, polyphenols can directly influence different points of the apoptotic process, and/or the expression of regulatory proteins. Although the bulk of data has been obtained in in vitro systems, a number of clinical studies suggesting a preventive and therapeutic effectiveness of polyphenols in vivo is available. However, a deeper knowledge of the underlying mechanisms responsible for the modulation of apoptosis by polyphenols, and their real effectiveness, is necessary in order to propose them as potential chemopreventive and chemotherapeutic candidates for cancer treatment.  相似文献   
65.
A general survey of fluorinated phosphazene polymers starting from their synthesis in 1965 to recent times is presented. Various types of fluorinated phosphazenes are described depending on the way fluorine atoms are connected to the polyphosphazene skeleton. The characterization, properties and practical utilization of these compounds in different domains are critically discussed.  相似文献   
66.

Object

The objective of this study is to propose a modified VARiable PROjection (VARPRO) algorithm specifically tailored for fitting the intravoxel incoherent motion (IVIM) model to diffusion-weighted magnetic resonance imaging (DW-MRI) data from locally advanced rectal cancer (LARC).

Materials and methods

The proposed algorithm is compared with classical non-linear least squares (NLLS) analysis using the Levenberg-Marquardt (LM) algorithm and with two recently proposed algorithms for ‘segmented’ analysis. These latter two comprise two consecutive steps: first, a subset of parameters is estimated using a portion of data; second, the remaining parameters are estimated using the whole data and the previous estimates. The comparison between the algorithms was based on the \(R^2\) goodness-of-fit measure: performance analysis was carried out on real data obtained by DW-MRI on 40 LARC patients.

Results

The performance of the proposed algorithm was higher than that of LM in 64 % of cases; ‘segmented’ methods were poorer than our algorithm in 100 % of cases.

Conclusion

The proposed modified VARPRO algorithm can lead to better fit of the IVIM model to LARC DW-MRI data compared to other techniques.
  相似文献   
67.
The influence of temperature on the kinetics and the morphology of silver deposits obtained from an air and water-stable ionic liquid (the 1-butyl-3-methyl imidazolium tetrafluoroborate) was studied by means of cyclic voltammetry and chronoamperometry. The nucleation and growth mechanisms have been investigated and the effect of temperature evaluated up to 200 °C. Dense, pure and very thin (about 0.3 μm) silver coatings, with decorative properties, have been obtained on commercial copper electrodes at different temperatures. The characterization of the deposits morphology has been performed by visual investigation and SEM microscopy. Data about thickness were acquired by Calotest® measurements. The deposits result constituted by pure silver as determined by combination of EDX microanalysis and Auger Electron Spectroscopy (AES). The deposition method promises to be a new, environmentally friendly, method for silver electrodeposition which is the reason for the absence of cyanide and volatile toxic solvents in the electroplating bath.  相似文献   
68.
Previous research, by R. M. Golinkoff and R. R. Rosinski (1976), used a picture-word interference task to show that skilled and less skilled comprehenders in the 3rd and 5th grades could retrieve the meaning of primer-level words equally well. With a similar task and comparable groups of children ( N = 64), the present study assessed the relationship between word difficulty and semantic access by using both the easy words and a new set of more difficult words. Retrieval of the meaning of these difficult words was least apparent for the less skilled 3rd graders, the group that had the most difficulty decoding these words. Results indicate that decoding ease and extraction of word meanings are related and also suggest that decoding ability must be considered a factor in reading comprehension. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
69.
Reducing food waste is a priority to move towards more sustainable food systems. Since agro-food by-products are often rich in healthy compounds, such as fibre, phytochemicals, protein, fatty acids, vitamins and minerals, the waste valorisation could move through their transformation into ingredients useful for the formulation of functional foods. Pasta is a staple food widely consumed all over the world representing an optimal carrier for nutrients delivery. The incorporation of ingredients of a high added value obtained by agro-industrial by-products in pasta can improve its nutritional value and provides several health benefits. At the same time, the inclusion of new ingredients could modify the physical, chemical and textural properties determining the change of the organoleptic characteristics of fortified pasta, affecting its acceptability. Thus, the preparation of new pasta formulations with high nutritional properties, good technological and sensory characteristics represents a challenge for the food industry.  相似文献   
70.
Heart failure (HF) prevalence is increasing among the aging population, and the mortality rate remains unacceptably high despite improvements in therapy. Myocardial ischemia (MI) and, consequently, ischemia/reperfusion injury (IRI), are frequently the basis of HF development. Therefore, cardioprotective strategies to limit IRI are mandatory. Nanocarriers have been proposed as alternative therapy for cardiovascular disease. Controlled reoxygenation may be a promising strategy. Novel nanocarriers, such as cyclic nigerosyl-nigerose (CNN), can be innovative tools for oxygen delivery in a controlled manner. In this study we analyzed new CNN-based formulations as oxygen nanocarriers (O2-CNN), and compared them with nitrogen CNN (N2-CNN). These different CNN-based formulations were tested using two cellular models, namely, cardiomyoblasts (H9c2), and endothelial (HMEC) cell lines, at different concentrations. The effects on the growth curve during normoxia (21% O2, 5% CO2 and 74% N2) and their protective effects during hypoxia (1% O2, 5% CO2 and 94% N2) and reoxygenation (21% O2, 5% CO2 and 74% N2) were studied. Neither O2-CNN nor N2-CNN has any effect on the growth curve during normoxia. However, O2-CNN applied before hypoxia induces a 15–30% reduction in cell mortality after hypoxia/re-oxygenation when compared to N2-CNN. O2-CNN showed a marked efficacy in controlled oxygenation, which suggests an interesting potential for the future medical application of soluble nanocarrier systems for MI treatment.  相似文献   
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